Please check my sentences gramatically(12.3)

Since you've mentioned it, I vaguely remember that it was when I was in middle school. E-mail was a convenient way to keep in touch with friends. Although they lived far from me. One day, I checked an e-mail sent from my friends. The e-mail had a problem, like a virus. As soon as I opened it, my PC was out of order. Even my hard disc was wiped out. I couldn't imagine that situation before that time, I felt like I was at the end of the world. I didn't know what I should do, I'm not sure if my friend sent me the e-mail that had a virus because I think my friend was attacked by hackers. Hackers would join my friend's ID and send virused e-mails pretending to be my friend. After that, I didn't check my e-mail when using my PC. Thanks to the advancement of technology, there's millions of anti-virus application which I installed one of those programs to protect my PC from the virus. Samsung phone has no stock. Finishing online game, I regret that I wasted my time. The interface of the game is complicated for novice.